The invention relates to exhaust aftertreatment filters for internal combustion engines, including diesel engines.
The invention of the noted parent ""152 application relates to exhaust emission devices for internal combustion engines, including diesel engines, and more particularly to catalytic converters and to filters. Various diesel exhaust aftertreatment systems require that the exhaust be directed through a catalytic component and also through a filter component to achieve emissions and/or particulate (e.g. soot) reduction. The parent invention provides a simple system combining these devices in a singular unit. In a desirable aspect, the parent invention further maintains exact axial alignment of the catalytic and filter flow channels and simplifies packaging.
The present invention initially grew out of attempts to solve customer-reported problems with stalled trucks due to clogged exhaust filters. It is known in the prior art to provide a cylindrical filter roll having a hollow center and a surrounding annulus with axially extending alternately sealed flow channels providing the filtering function. The hollow center or core is plugged, to block flow therethrough, and force exhaust to flow through the filter section. During usage, as the filter section becomes clogged, the truck may stall. One possible solution is to eliminate the central blocking plug. However, this may weaken the unit by eliminating the central structural support provided by such plug, and also leads to increased particulate emission, i.e. a portion of the exhaust would be unfiltered. The present invention provides various solutions and trade-offs in combination. In one desirable combination, a combined catalytic converter and filter is provided. In another desirable combination, improved filter regeneration is provided. Other desirable aspects and features will become apparent upon review of the following specification.